Sen. Ted Cruz is goading a group of House tea partyers who have wreaked havoc with the leadership in the past to demand that the must-pass spending legislation cut off all federal money for Planned Parenthood.

They are putting the pressure on Congress’ Republican leaders who are facing stark tests as they fight to keep the government open past month’s end, amid fears a shutdown could imperil their party’s White House ambitions.

For House Speaker John Boehner, R-Ohio, any wrong move could throw his very future into question, opening him to a threatened showdown vote on the floor of the House over whether he can remain in his job. If that happens, there is no certain outcome.

Senate Majority Leader Mitch McConnell, R-Ky., must contend with the ambitions of several GOP presidential candidates

Cruz has made it his business to oppose the Kentuckian at every turn, even taking to the Senate floor to accuse him of lying.

The efforts by the House tea partyers follows the disclosure of secretly recorded videos in which Planned Parenthood officials are shown discussing how they acquire fetal parts for medical research.

Such a bill could not pass the Senate and would face a certain veto from President Barack Obama, raising the prospect of a partial government shutdown like the one two years ago in a similar struggle over the health care law.

"There's nothing principled about the idea of another government shutdown," the president said in his weekend radio address."

With less than two weeks to the Oct. 1 deadline, there remains no endgame — unless it's divine intervention in the form of an historic address from Pope Francis to a joint meeting of Congress on Thursday.

And for the majority of congressional Republicans, who have little interest in palace intrigue or shutdown talk, the infighting and disarray serves only as a depressing reminder of the GOP's repeated failures to capitalize on historic congressional majorities to advance a governing agenda that could help their party retake the presidency. Nor does it bode well for how Republicans navigate fights yet to come this year, including a potentially market-rattling struggle over raising the government's borrowing limit.

"There are some in the House who are using serious governance issues to score cheap political points against the speaker," said Rep. Charlie Dent, R-Pa. "Shutting down the government is not in our political interest, it will undermine the Republican brand and it will hurt whoever the Republican nominee is in November."

Such warnings are dismissed by the most unyielding conservatives in the House, who insist that the only way to force Obama to reckon with their demands to defund Planned Parenthood is by including it in must-pass spending legislation to keep the government open. The tactic has failed twice before — two years ago over the health care law and earlier this year in an unsuccessful revolt against Obama's executive actions limiting deportations.

Nonetheless, some Republicans continue to insist that their leaders must hold firm, despite the prospect of an Obama veto and even though McConnell has repeatedly made clear that legislation to defund Planned Parenthood cannot pass the Senate's 60-vote threshold, which demands compromise with minority Democrats. They reject such logic as capitulation.

"There will be a significant number of Republicans who will say, 'I will vote no on any bill that has an opportunity to defund Planned Parenthood and fails to do so,'" said Rep. Steve King, R-Iowa, who includes himself in that group and also says he would vote to end Boehner's tenure as speaker if given the opportunity. "This is an organic situation that is festering and the pressure's building, and I don't know that I can predict what will happen. But I've never seen it get to this point where there's this much discontent."

The unrest is not just among the 30 to 40 tea partyers who want to push the Planned Parenthood issue to the brink of a shutdown. The much larger number of more pragmatic House members are also increasingly disgusted that a small, vocal minority has repeatedly caused problems and thrown their agenda into disarray, without leadership being able to stop them.

This time around some would like to see Boehner ignore the rebels and go straight to Democrats to make a deal.

But that could precipitate a disgruntled tea party lawmaker into bringing a "motion to vacate the chair," which would force a vote on Boehner. Most believe the speaker, who enjoys widespread GOP support, would survive such a vote, in part because there's no obvious candidate to replace him aside from members of his own leadership team, who've disavowed the effort. But it could require the cooperation of Democrats, making the outcome impossible to predict and ensuring great intrigue.

"We need a speaker and I haven't seen anybody who says they want the job other than John Boehner," said Rep. Mike Conaway, R-Texas. "If you're going to have a palace revolt, you need someone to lead that revolt."

Behind the move are leaders of the House Freedom Caucus, a GOP faction whose members are among the chamber's most conservative. Among the most outspoken are Reps. Jim Jordan, R-Ohio and Mick Mulvaney, R-S.C., the latter of whom has rounded up more than 30 Republicans who have vowed to oppose any stopgap spending measure that fails to take away federal funding of Planned Parenthood.

"If we have the debate," Jordan said recently, "the logic and common sense are on our side."